Mounting Page
12
Document id: 7000 108-011 A2
is located on the same level as other antennas, the distance apart
should be at least 10 meters.
The AIS VHF antenna should be installed safely away from
interfering high-power radiating sources like radar and other
transmitting radio antennas, preferably at least 3 meters away from
and out of the transmitting beam.
2.5.4
Clear view of the horizon
The AIS VHF antenna should be placed in an elevated position that
is as free as possible with a minimum of 2 meters in horizontal
direction from constructions made of conductive materials. The
antenna should not be installed close to any large vertical
obstruction. The objective for the AIS VHF antenna is to see the
horizon freely through 360 degrees.
2.5.5 Antenna
height
The AIS is using VHF radio frequencies, which propagation
characteristics are close to line of sight. The higher antenna location
is, the longer the range will be.
2.5.6 Cabling
The cable should be kept as short as possible to minimise attenuation
of the signal. Double shielded coaxial cable equal or better than
RG214 is recommended to minimise the effects from
electromagnetic interference from high power lines, radar or other
radio transmitter cables, see Appendix
[
A.6
]
– VHF-cable selector.
2.5.7 Cable
mounting
Coaxial cables should be installed in separate signal cable
channels/tubes and at least 10 cm away from power supply cables.
Crossing of cables should be done at right angles (90°).
Coaxial cables should not be exposed to sharp bends, which may
lead to a change of the characteristic impedance of the cable. The
minimum bending radius should be 5 times the cable's diameter.
All outdoor installed connectors should be weatherproofed, e.g. with
shrink tubing, watertight seal tape or butyl rubber tape and plastic
tape sealing, to protect against water penetration into the antenna
cable.
Secure the cable properly, close to the cable ends.
2.5.8 Grounding
Coaxial down-leads must be grounded. The coaxial shielding screen
should be connected to ground at one end.
2.6 GPS
antenna
The R4 Transponder shall be connected to a GPS AeroAntenna, AT
575-68 or equivalent GPS antenna.
